Phixius

Question: In the scene where Evan visits an institutionalized Lenny locked in restraints, Lenny accuses him of having known on the day of the junkyard (where Lenny stabbed Tommy with a shard) that "something big was going to happen" and that Evan "should be where I am". How did Lenny know that Evan foresaw the "future" as it were, and that he changed the course of events which lead to his imprisonment?

Question: There's one thing that bothers me. It's when Evan ends up in mental hospital, and his brain is once again attacked by torrent of new memories, then we see very fast switching pictures of various faces, with lots of mixed voices in the background. What is the meaning of this?